Death is the ceasing of vitality (Ayu), heat (usama) and consciousness (vinnana). Buddhism denies the existence of a transmigrating soul created by a supreme soul which means nothing comes out from one body and enters another (Rejects the idea of eternalism).
Everything is in accordance with dependent origination: everything arises because of a preceding event, everything is interlinked. Craving gives rise to Clinging which gives rise to Becoming (continuity of the life process activated by kamma) and then to Rebirth as per dependent origination. This also supports the 2nd noble truth that says because of craving it gives rise to a new being consisting of 5 aggregates of clinging which are suffering.
4 types of death
Exhaustion of the force of reproductive kamma that gave rise to the birth in question.
Expiration of lifespan (Ayu)
Simultaneous exhaustion of both reproductive kamma and lifespan (Ubhaya)
Action of a stronger kamma that suddenly cuts off the power of reproductive kamma before the expiry of the life-term
This first three types of death are called timely death but the last one is called untimely death.
Objects presented to the mind before death
A dying person is presented with kamma, kamma nimitta or Gati Nimitta at the death moment
Kamma
These are good and bad volitions of the person
Heavy weighty (Garuka) Kamma: This is either weighty or serious kamma which can be good or bad. When it ripens, it produces results this life or in the next for certain. If it is good, it is purely mental staes as in the case of Jhana. It can be bad kamma if one conducts matricides, parricides, murder of arahant, wounding the buddha and creation of schism in the sangha. If this is absent, he may recollect the action done immediately before death, death proximate kamma.
Death-proximate (Asama) kamma: This is what one does or remembers immediately before the moment of dying. It plays a part in determining the future birth. Hence many Buddhist countries have customs to remind the dying person of the good deeds and make him do good acts on his death bed. Sometimes a bad person may die happily and receive good birth if he remembers or does a good act at the last moment. If this is absent, a habitual kamma is presented to him.
Habitual(Acinna) kamma: This is what one constantly performs and recollects every day or every week during this lifetime. At death moment unless influenced by other circumstances, one usually recalls to mind one’s habitual deeds. For example, a butcher may die yelling like an animal because he slaughters pigs daily for a living. If above are absent, then cumulative reserves of endless past becomes the object of dying thought.
Cumulative (Katatta) kamma: This literally means “because done”. All actions not included above and those actions soon forgotten belong to this category. This is the reserve fund of a particular being.
2. Kamma Nimitta
Any sight, sound, smell, taste, touch or idea which was obtained at the time of commission of the kamma. For example, knives in case of butcher, patients in case of doctor, object of worship in case of devotee.
3. Gati Nimitta
Some sign of the place where one is destined to be reborn like a symbol of destiny
It is always a physical sight, presented to mind door like a dream
Psychologically these mental stages maybe considered like illusion, hallucination or delusion
People whose minds are lucid and unconfused at their dying moments may not experience any death bed visions.
Five visions of dying person maybe hellish fires (rebirth in hell), Animals and forest (rebirth in animal realm), Dark spirit images (reborn as ghosts), deceased parents and relatives (reborn as humans) and celestial mansions and chariots (reborn in celestial realms).
The dying consciousness In abhidhamma, a normal thought process lasts for 17 thought moments (Citta) in which Javana process lasts for 7 thought moments. Javana is important ethically as it is during these moments good and evil is done and kamma is performed.
But before death, the javana is weak and runs only for 5 thought moments. This last javana process is very important as it determines the reproductive kamma of next life. Next the registering consciousness which identifies the object may or may not follow. After this, the death consciousness (cuticitta), the last thought moment to be experience in present life.
Upon death, the last consciousness passes away conditioning the arising of new consciousness called rebirth consciousness (Patisandhi) in a new body or form of birth. The new being is neither absolute the same as past owing to its different composition nor totally different, being the identical stream of kammic energy.
There is no room for an intermediate state, the transition of the flux is instantaneous. Rebirth takes place immediately. What actually conditions rebirth is not the death consciousness but the last javana process. If it is wholesome, rebirth takes place in a happy realm. If it is unwholesome, rebirth takes place in a woeful realm.
How Rebirth takes place
Three conditions must be present for rebirth to take place:
Mother and Father must unite
Mother’s womb condition ready (ovum is ripe)
The being to be born is present
4 types of beings
Egg born beings: creatures such as bird, reptiles and fish
Womb-born beings: creatures such as humans, mammals
Moisture born beings: creatures such as certain insects that take moisture as material for their growth
Spontaneous beings: Generally invisible to the human eye. Conditioned by past kamma, they appear suddenly, independently of parents. Such as brahmas, devas, petas, asuras and hell-beings.
4 planes of existence to be reborn: 31 realms
Sensual plane of misery: 4 realms namely hell (niraya), animal, ghost (Peta) and demons (asuras). Rebirth in this plane is conditioned by unwholesome reproductive kamma at moment of death.
Sensual plane of bliss: 7 sensual states of bliss comprising of human realm and 6 heavenly realms, rebirth as human or devas. This is conditioned by superior wholesome reproductive kamma. However, rebirth as a degraded human who is blind, deaf, deformed is conditioned by inferior wholesome reproductive kamma.
Form plane: Rebirth in one of the 16 states of brahma gods that is conditioned by jhanas.
Formless plane: Rebirth in one of the 4 states of formless brahma gods is conditioned by arupa jhana: Realm of infinite space, realm of infinite consciousness, realm of nothingness and realm of neither perception nor non-perception.
So in total, the four planes comprise 31 realms of existence